From c86bd4e134c23146c216f9ff97e03781d55991b6 Mon Sep 17 00:00:00 2001
From: Maxim Khramtsov <khraks.mamtsov@gmail.com>
Date: Wed, 26 Jun 2024 00:26:44 +0200
Subject: [PATCH] Support unification for `Micro` module (#3078)

Co-authored-by: maksim.khramtsov <maksim.khramtsov@btsdigital.kz>
Co-authored-by: Tim <hello@timsmart.co>
---
 .changeset/rare-cameras-explain.md |  5 +++++
 packages/effect/dtslint/Unify.ts   | 15 +++++++++++++--
 packages/effect/src/Micro.ts       | 21 ++++++++++++++++++++-
 3 files changed, 38 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/rare-cameras-explain.md

diff --git a/.changeset/rare-cameras-explain.md b/.changeset/rare-cameras-explain.md
new file mode 100644
index 0000000000..e6b3bdae01
--- /dev/null
+++ b/.changeset/rare-cameras-explain.md
@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+Support unification for Micro module
diff --git a/packages/effect/dtslint/Unify.ts b/packages/effect/dtslint/Unify.ts
index 9d5889d12b..4aabe4784d 100644
--- a/packages/effect/dtslint/Unify.ts
+++ b/packages/effect/dtslint/Unify.ts
@@ -1,4 +1,6 @@
+import type * as Effect from "effect/Effect"
 import * as Either from "effect/Either"
+import type * as Micro from "effect/Micro"
 import type * as Option from "effect/Option"
 import type * as Stream from "effect/Stream"
 import * as Unify from "effect/Unify"
@@ -23,7 +25,16 @@ Unify.unify(<N>(n: N) => Math.random() > 0 ? Either.right(n) : Either.left("ok")
 // $ExpectType Either<number, string>
 Unify.unify(Math.random() > 0 ? Either.right(10) : Either.left("ok"))
 
-// $ExpectType Stream<0 | 1, never, never>
+// $ExpectType Stream<0 | "a", "b" | 1, "c" | 2>
 export type SU = Unify.Unify<
-  Stream.Stream<0> | Stream.Stream<1>
+  Stream.Stream<0, 1, 2> | Stream.Stream<"a", "b", "c">
+>
+
+// $ExpectType Micro<0 | "a", "b" | 1, "c" | 2>
+export type MU = Unify.Unify<
+  Micro.Micro<0, 1, 2> | Micro.Micro<"a", "b", "c">
+>
+// $ExpectType Effect<0 | "a", "b" | 1, "c" | 2>
+export type EU = Unify.Unify<
+  Effect.Effect<0, 1, 2> | Effect.Effect<"a", "b", "c">
 >
diff --git a/packages/effect/src/Micro.ts b/packages/effect/src/Micro.ts
index 25a73c5157..d118588c61 100644
--- a/packages/effect/src/Micro.ts
+++ b/packages/effect/src/Micro.ts
@@ -6,7 +6,7 @@
  */
 import type { Channel, ChannelTypeId } from "./Channel.js"
 import * as Context from "./Context.js"
-import type { Effect, EffectTypeId } from "./Effect.js"
+import type { Effect, EffectTypeId, EffectUnify, EffectUnifyIgnore } from "./Effect.js"
 import * as Effectable from "./Effectable.js"
 import * as Either from "./Either.js"
 import { constTrue, constVoid, dual, identity, type LazyArg } from "./Function.js"
@@ -24,6 +24,7 @@ import type { ReadonlyRecord } from "./Record.js"
 import type { Sink, SinkTypeId } from "./Sink.js"
 import type { Stream, StreamTypeId } from "./Stream.js"
 import type { Concurrency, Covariant, Equals, NoInfer, NotFunction, Simplify } from "./Types.js"
+import type * as Unify from "./Unify.js"
 import { YieldWrap, yieldWrapGet } from "./Utils.js"
 
 /**
@@ -64,9 +65,27 @@ export type runSymbol = typeof runSymbol
 export interface Micro<out A, out E = never, out R = never> extends Effect<A, E, R> {
   readonly [TypeId]: Micro.Variance<A, E, R>
   readonly [runSymbol]: (env: Env<any>, onResult: (result: Result<A, E>) => void) => void
+  [Unify.typeSymbol]?: unknown
+  [Unify.unifySymbol]?: MicroUnify<this>
+  [Unify.ignoreSymbol]?: MicroUnifyIgnore
   [Symbol.iterator](): MicroIterator<Micro<A, E, R>>
 }
 
+/**
+ * @category models
+ * @since 3.4.3
+ */
+export interface MicroUnify<A extends { [Unify.typeSymbol]?: any }> extends EffectUnify<A> {
+  Micro?: () => A[Unify.typeSymbol] extends Micro<infer A0, infer E0, infer R0> | infer _ ? Micro<A0, E0, R0> : never
+}
+
+/**
+ * @category models
+ * @since 3.4.3
+ */
+export interface MicroUnifyIgnore extends EffectUnifyIgnore {
+  Effect?: true
+}
 /**
  * @category type lambdas
  * @since 3.4.1